Which numeral system uses the digits 0-7?

The octal number system is specifically designed to use the digits from 0 to 7, making it a base-8 numeral system. This means that it includes eight distinct symbols, which are 0, 1, 2, 3, 4, 5, 6, and 7. In the octal system, each digit's place value is a power of 8, and it serves as a convenient way to represent binary numbers in a more compact form since one octal digit corresponds to three binary digits.

The other numeral systems mentioned have different ranges of digits. For example, the binary number system only uses two digits (0 and 1), while the decimal number system uses ten digits (0 through 9), and the hexadecimal system utilizes sixteen symbols, which include the digits 0 to 9 and the letters A to F. Thus, the distinction of the octal system lies in its unique set of digits and base, firmly identifying it as the correct answer in this context.